A man-made bat cave in Tennessee is looking for tenants. An hour northwest of Nashville, the artificial cave is built to give thousands of bats a haven from a devastating infection called white-nose syndrome.

Millions of bats in the Northeast have died from the infection since it first showed up a few years ago. The culprit is an invasive fungus that grows in caves. When bats hibernate inside, they wake up with faces covered in white fuzz and often wind up starving or freezing to death.

"It's kind of terrifying," says Ann Froschauer, communications leader on white-nose syndrome for the U.S. Fish and Wildlife Service in Massachusetts.

Since it was first found in New England six years ago, white-nose has spread, from Canada to Alabama. Froschauer witnessed firsthand one of the worst die-offs. She says the cave floor was littered with tiny bones like pine needles.

"I knew that that's not what it was, but it was just really impossible for me to understand there's ... an inch-and-a-half- to 2-inch-thick carpet of just bones on the floor here, and skulls," she says, "and if you crouch down and look, you can see there's little clumps of fur and decaying tissue."

Finding A Solution, Quickly

Scientists fear regional extinction for some species in a matter of years, leaving precious little time for a solution. Some are working on treating the infection and developing a vaccine. Biologist Cory Holliday says those approaches are valid, but hard to do on a meaningful scale.

"None of it is environmental changes to treat thousands of bats, or to help save thousands of bats," he says.

That's why Holliday's employer, The Nature Conservancy, fronted a big part of the $300,000 to hire a construction crew and fire up some earthmovers.

The concrete box buried in a hillside is almost as long as a basketball court, but only half as wide. It's high-tech inside, with surveillance cameras that detect heat without getting warm or making any noise — even ultrasonic sound could be a deal-breaker to bats moving in. To power the gear, workers screw in electric panels.

The idea is to offer bats a safe winter home, where every summer humans could go inside and clean out any lurking fungus, keeping white-nose syndrome in check.

Open House

Holliday hopes a few hundred bats will make it their home this winter, with more to follow.

"If we get the conditions right, there could be over 200,000 bats here, is what we've estimated," he says.

The clock is ticking. Holliday is hoping to lure bats over from a nearby natural cave, where early stages of white-nose were just found.

"We will be broadcasting sort of ultrasonic bat calls from around the entrance area, just hoping to draw them in," he says.

The disease often takes just a few winters to hit a kind of critical mass and ravage a sleeping population. Holliday hopes before it comes to that, the new cave can prove a viable model. He'd rather count bats in the air, than on the ground.

A new living space in Tennessee is seeking new tenants, tenants that are quiet during the day and like bugs. Oh, yeah, this living space is a cave, a man-made cave an hour northwest of Nashville.

From member station WPLN, Daniel Potter says it was built to give bats a safe haven from a devastating infection called white-nose syndrome.

DANIEL POTTER, BYLINE: Millions of bats in the northeast have died from white-nose syndrome since it first showed up a few years ago. The culprit is an invasive fungus that grows in caves. When bats hibernate inside, they wake up with faces covered in white fuzz and often wind up starving or freezing to death.

ANN FROSCHAUER: It's kind of terrifying.

POTTER: Ann Froschauer works for the U.S. Fish and Wildlife Service in Massachusetts. Since it was first found in New England six years ago, white-nose has spread from Canada to Alabama. Froschauer witnessed firsthand one of the worst die-offs. She says the cave floor was littered with tiny bones like pine needles.

FROSCHAUER: I knew that that's not what it was, but it was just really impossible for me to sort of understand there's, you know, an inch-and-a-half to two-inch thick carpet of just bones on the floor here and skulls, and if you crouch down and look, you can see there's little clumps of fur and decaying tissue.

POTTER: Scientists fear regional extinction for some species in a matter of years, leaving precious little time for a solution. Some are working on treating the infection and developing a vaccine. Biologist Cory Holliday says those approaches are valid but hard to do on a meaningful scale.

CORY HOLLIDAY: None of it is environmental changes to treat thousands of bats or to help save thousands of bats.

POTTER: That's why Holliday's employer, The Nature Conservancy, fronted a big part of the $300,000 to hire a construction crew and fire up some earthmovers.

(SOUNDBITE OF MACHINERY)

POTTER: It's a project unlike most any other Elko Husinovic's worked on.

ELKO HUSINOVIC: I was wondering what it is, what this place is for, but my boss, he's told me it's for bats, whatever. I was like cool.

POTTER: The concrete box buried in hillside is almost as long as a basketball court but only half as wide. It's high-tech inside, with surveillance cameras that detect heat without getting warm or making any noise. That's because even ultrasonic sound could be a deal-breaker to bats moving in. To power the gear, workers screw in electric panels.

(SOUNDBITE OF MACHINERY)

POTTER: The idea is to offer bats a safe winter home where, every summer, humans could go inside and clean out any lurking fungus, keeping white-nose syndrome in check. Cory Holliday hopes a few hundred bats will make it their home this winter, with more to follow.

HOLLIDAY: If we get the conditions right, there could be, you know, over 200,000 bats here is what we've estimated.

POTTER: The clock is ticking. Holliday is hoping to lure bats over from a nearby natural cave, where early stages of white-nose were just found.

HOLLIDAY: And we will be broadcasting sort of ultrasonic bat calls from around the entrance area, just hoping to draw them in.

POTTER: The disease often takes just a few winters to hit a kind of critical mass and ravage a sleeping population. Holliday hopes before it comes to that, the new cave can prove a viable model. He'd rather count bats in the air than on the ground. For NPR News, I'm Daniel Potter in Nashville. Transcript provided by NPR, Copyright NPR.